Spa basin



FIG. 1 is a rear perspective view of a spa basin showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a right side elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a front elevation view thereof;

FIG. 7 is a rear elevation view thereof; and,

FIG. 8 is another perspective view thereof, shown in environmental use.

The broken lines showing of a chair and basin support in FIG. 8 are for illustrative purpose only and form no part of the claimed design. 

The ornamental design for a spa basin, as shown and described. 